Commonly-owned U.S. Pat. No. 5,465,443 to Rice, et al., whose contents are incorporated herein in their entirety by this reference, describes various discs for, principally, automatic swimming pool cleaners. Extending upward from the upper surfaces of the discs are multiple fins. By contrast, except for a downwardly-projecting ramp positioned about a central aperture of the disc, its lower surface is generally planar.
U.S. Pat. No. 5,617,606 to Scott, II, et al., also commonly owned with this application, details other discs for automatic swimming pool cleaners. Projecting above the majority of the upper surfaces are one or more flutes, whose edges may be curved or straight as desired. Similarly projecting upward at the outer peripheries of the discs may be a raised, or upturned, lip.
Like the discs of the Rice patent, those of the Scott, II patent may include annular ramps projecting downwardly from their lower surfaces. Otherwise, however, the lower surfaces of the discs are generally flat, again similar to those of the discs of the Rice patent. The contents of the Scott, II patent are incorporated herein in their entirety by this reference.